The present invention relates to an electric pump that draws in and discharges fluid such as oil.
Conventionally, electric pumps as disclosed in Japanese Patent No. 4042050 have been proposed. The electric pump includes a metal pump housing, which has a shaft support hole for rotationally supporting a middle part of a rotary shaft, and a motor case, which is fixed to the pump housing. A motor stator is provided in the motor case, and a motor rotor, which is provided on the end of the rotary shaft, is accommodated inside the motor stator. The motor case is formed of plastic and is insert-molded to cover the motor stator. A mounting portion for mounting a circuit substrate is integrally formed on a part of the motor case that is opposite to the part to which the pump housing is fixed. A circuit substrate that contains circuit components is mounted on the mounting portion, and the circuit substrate and the circuit components are covered by a cover fixed to the motor case.
However, in the electric pump as above described, heat generated at a motor section including the motor stator and the motor rotor is not easily dissipated by the plastic motor case. Also, since the heat generated at the motor section is directly transferred from the motor case to the circuit substrate, the heat may cause damage on the circuit components. That is, the heat generated at the motor section may be transferred from the mounting portion integrally formed on the motor case directly to the circuit substrate.